39,976 research outputs found
System for and method of freezing biological tissue
Biological tissue is frozen while a polyethylene bag placed in abutting relationship against opposed walls of a pair of heaters. The bag and tissue are cooled with refrigerating gas at a time programmed rate at least equal to the maximum cooling rate needed at any time during the freezing process. The temperature of the bag, and hence of the tissue, is compared with a time programmed desired value for the tissue temperature to derive an error indication. The heater is activated in response to the error indication so that the temperature of the tissue follows the desired value for the time programmed tissue temperature. The tissue is heated to compensate for excessive cooling of the tissue as a result of the cooling by the refrigerating gas. In response to the error signal, the heater is deactivated while the latent heat of fusion is being removed from the tissue while the tissue is changing phase from liquid to solid
A modeling-based evaluation of isothermal rebreathing for breath gas analyses of highly soluble volatile organic compounds
Isothermal rebreathing has been proposed as an experimental technique for
estimating the alveolar levels of hydrophilic volatile organic compounds (VOCs)
in exhaled breath. Using the prototypic test compound acetone we demonstrate
that the end-tidal breath profiles of such substances during isothermal
rebreathing show characteristics that contradict the conventional pulmonary
inert gas elimination theory due to Farhi. On the other hand, these profiles
can reliably be captured by virtue of a previously developed mathematical model
for the general exhalation kinetics of highly soluble, blood-borne VOCs, which
explicitly takes into account airway gas exchange as major determinant of the
observable breath output.
This model allows for a mechanistic analysis of various rebreathing protocols
suggested in the literature. In particular, it clarifies the discrepancies
between in vitro and in vivo blood-breath ratios of hydrophilic VOCs and yields
further quantitative insights into the physiological components of isothermal
rebreathing.Comment: 21 page
Medical Support and Findings of the Skylab Program
Specific equipment used in carrying out Skylab medical experiments is outlined and illustrated. Also included are reviews of the techniques, frequency, and protocols of the tests designed to study the long term effects of weightlessness on the human body. In-flight investigations were an evaluation of the cardiovascular system, a study of metabolic activity, investigations in the field of neurophysiology, the determination of changes in body fluids, a precise measurement of total body metabolism, and a study of crew performance by use of a time and motion experiment. Significant data obtained from in-flight and postflight tests are outlined
Fine and ultrafine particle number and size measurements from industrial combustion processes : primary emissions field data
This study is to our knowledge the first to present the results of on-line measurements of residual nanoparticle numbers downstream of the flue gas treatment systems of a wide variety of medium- and large-scale industrial installations. Where available, a semi-quantitative elemental composition of the sampled particles is carried out using a Scanning Electron Microscope coupled with an Energy Dispersive Spectrometer (SEM-EDS). The semi-quantitative elemental composition as a function of the particle size is presented. EU's Best Available Technology documents (BAT) show removal efficiencies of Electrostatic Precipitator (ESP) and bag filter dedusting systems exceeding 99% when expressed in terms of weight. Their efficiency decreases slightly for particles smaller than 1 mu m but when expressed in terms of weight, still exceeds 99% for bag filters and 96% for ESP. This study reveals that in terms of particle numbers, residual nanoparticles (NP) leaving the dedusting systems dominate by several orders of magnitude. In terms of weight, all installations respect their emission limit values and the contribution of NP to weight concentrations is negligible, despite their dominance in terms of numbers. Current World Health Organisation regulations are expressed in terms of PM2.5 wt concentrations and therefore do not reflect the presence or absence of a high number of NP. This study suggests that research is needed on possible additional guidelines related to NP given their possible toxicity and high potential to easily enter the blood stream when inhaled by humans
Heart Beat Characterization from Ballistocardiogram Signals using Extended Functions of Multiple Instances
A multiple instance learning (MIL) method, extended Function of Multiple
Instances (FUMI), is applied to ballistocardiogram (BCG) signals produced by
a hydraulic bed sensor. The goal of this approach is to learn a personalized
heartbeat "concept" for an individual. This heartbeat concept is a prototype
(or "signature") that characterizes the heartbeat pattern for an individual in
ballistocardiogram data. The FUMI method models the problem of learning a
heartbeat concept from a BCG signal as a MIL problem. This approach elegantly
addresses the uncertainty inherent in a BCG signal e. g., misalignment between
training data and ground truth, mis-collection of heartbeat by some
transducers, etc. Given a BCG training signal coupled with a ground truth
signal (e.g., a pulse finger sensor), training "bags" labeled with only binary
labels denoting if a training bag contains a heartbeat signal or not can be
generated. Then, using these bags, FUMI learns a personalized concept of
heartbeat for a subject as well as several non-heartbeat background concepts.
After learning the heartbeat concept, heartbeat detection and heart rate
estimation can be applied to test data. Experimental results show that the
estimated heartbeat concept found by FUMI is more representative and a more
discriminative prototype of the heartbeat signals than those found by
comparison MIL methods in the literature.Comment: IEEE EMBC 2016, pp. 1-
A review of the biology and management of horseshoe crabs, with emphasis on Florida populations
In Florida, some horseshoe crabs are fished for eel bait, but they are fished principally by the marine-life industry, which collects the animals live for resale as aquarium, research, or educational specimens. The regulations for the horseshoe crab fisheries are developed by each state in compliance with the Atlantic States Marine Fisheries Commission (ASMFC) Horseshoe Crab Management Plan. This report was written to provide information on the biology,
stock status, and management of horseshoe crabs and
the implications relevant to the request for an increased
bag limit by harvesters in the marine-life industry
Great Bay Coast Watch: A Citizen Water Monitoring Program Volunteer Water Quality Monitoring Manual, 2004
The Great Bay Coast Watch is citizen volunteers, working within the UNH Cooperative Extension/NH Sea Grant Program, protecting the long-term health and natural resources of New Hampshire’s coastal waters and estuarine systems through monitoring and education projects.
The purpose of this document is to present step-by-step instructions for conducting water quality testing in support of the Great Bay Coast Watch (GBCW)
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